the first index of Partial segment when package LL-HLS contents

Hi,
The first index of Partial segment is 0 according to Protocol Extension for Low-Latency HLS (Preliminary Specification)
and draft-pantos-hls-rfc8216bis-07. My Apple LL-HLS packager use this rule. But it seems apple LL-HLS origin sample use 1 for first index. This is the error log when I use AVPlayer in IOS 14 beta to playback our content. This error always are reproduced when AVPlayer query progindex.m3u8 with HLSpart=6. The last index is 5 if first index is 0.
Is this a already issue in AVPlayer?

2020-07-13 09:56:11.872200+0800 HLSCatalog[411:14251] Perf – Playback started in 0.33 seconds

2020-07-13 09:56:14.182182+0800 HLSCatalog[411:14081] [] [09:56:14.182]
remoteXPCItem
GetObjectID signalled err=-17221
(kFigPlayerErrorServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayer
RemoteXPC.m:475

2020-07-13 09:56:14.182489+0800 HLSCatalog[411:14081] [] [09:56:14.182]
remoteXPCItemGetObjectID signalled err=-17221
(kFigPlayerError
ServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayerRemoteXPC.m:475
2020-07-13 09:56:14.183973+0800 HLSCatalog[411:14081] [] [09:56:14.184]
remoteXPCItem
GetObjectID signalled err=-17221
(kFigPlayerErrorServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayer
RemoteXPC.m:475

2020-07-13 09:56:14.184215+0800 HLSCatalog[411:14081] [] [09:56:14.184]
remoteXPCItemGetObjectID signalled err=-17221
(kFigPlayerError
ServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayerRemoteXPC.m:475

2020-07-13 09:56:14.192352+0800 HLSCatalog[411:14081] [] [09:56:14.192]
remoteXPCItem
GetObjectID signalled err=-17221
(kFigPlayerErrorServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayer
RemoteXPC.m:475
2020-07-13 09:56:14.192484+0800 HLSCatalog[411:14081] [] [09:56:14.192]
remoteXPCItemGetObjectID signalled err=-17221
(kFigPlayerError
ServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayerRemoteXPC.m:475

2020-07-13 09:56:14.192656+0800 HLSCatalog[411:14081] [] [09:56:14.193]
remoteXPCItem
GetObjectID signalled err=-17221
(kFigPlayerErrorServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayer
RemoteXPC.m:475

2020-07-13 09:56:14.193736+0800 HLSCatalog[411:14081] [] [09:56:14.194]
remoteXPCItemGetObjectID signalled err=-17221
(kFigPlayerError
ServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayerRemoteXPC.m:475
2020-07-13 09:56:14.194567+0800 HLSCatalog[411:14081] [] [09:56:14.195]
remoteXPCItem
GetObjectID signalled err=-17221
(kFigPlayerErrorServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayer
RemoteXPC.m:475

Error 1: Optional("Cannot Complete Action")

2020-07-13 09:56:14.203863+0800 HLSCatalog[411:14250] [] [09:56:14.204]
remoteXPCPlayerGetObjectID signalled err=-17221
(kFigPlayerError
ServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayerRemoteXPC.m:580
2020-07-13 09:56:14.206323+0800 HLSCatalog[411:14250] [] [09:56:14.206]
remoteXPCPlayer
GetObjectID signalled err=-17221
(kFigPlayerErrorServerConnectionLost) (Server connection was lost) at
/Library/Caches/com.apple.xbs/Sources/EmbeddedCoreMedia/EmbeddedCoreMedia-2737.4.1.1/Prototypes/Player/ClientServer/FigPlayer
RemoteXPC.m:580
the first index of Partial segment when package LL-HLS contents
 
 
Q